Additively formed rotor component for electric machine and method of forming

ABSTRACT

Disclosed within are a structure and method for forming a component for a rotor to be used in an electric machine. The formed rotor components can include a rotor assembly or rotor shaft. The rotor assembly can include a plurality of poles spaced about a rotor core. The plurality of poles can include a pole shoe or pole body. Quasi-laminations that can result in a unitary structure that includes support structures can be used to form all or a portion of the pole shoe or pole body.

BACKGROUND

Electric machines, such as electric motors or electric generators, areused in energy conversion. Such an electrical machine can include astator and a rotor. The rotor can be rotated relative to the stator togenerate electrical energy or can be rotated relative to the stator as aresult of changing magnetic fields induced in windings of the stator.Such electrical machinery can be included in, by way of non-limitingexample, a gas turbine engine.

BRIEF DESCRIPTION

Aspects of the disclosure relate to a rotor assembly for an electricmachine that includes a rotor core, a plurality of poles, the pluralityof poles spaced about the rotor core, each pole of the plurality ofpoles having a pole body extending from the rotor core towards a poleshoe defining a curved peripheral surface. At least a portion of atleast one of the pole shoe or the pole body includes quasi-laminationsdefined along at least a portion of an axial length of the at least aportion of the at least one of the pole shoe or the pole body and amethod for manufacturing.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 schematically illustrates a rotor assembly for an electricmachine according to aspects disclosed herein.

FIG. 2 schematically illustrates a pole of the rotor assembly of FIG. 1,with all other portions of the rotor assembly removed for clarity.

FIG. 3 schematically illustrates a top view of the pole of FIG. 2.

FIG. 4 schematically illustrates, according to another aspect disclosedherein, voids defined by support structures.

FIG. 5 illustrates a method for manufacturing a rotor for an electricalmachine.

DETAILED DESCRIPTION

Conventional methods of manufacturing an electrical machine orcomponents therefore can include, for instance, punching, stamping, orcutting laminations to shape, stacking the oxidized laminations to forma rotor core, winding coils made of insulated wire, inserting slotliners and coils into slots of the rotor core, sliding slot wedges atthe top of a slot, forming end turns, shrinking/fitting the rotor coreonto a pre-machined shaft, and then performing final machining. Whilesuch methods can be used to form satisfactory electric machines andcomponents therefore, such methods can be technically complex,inefficient, and costly.

Therefore, improved methods for manufacturing electric machines thataddress one or more of the challenges noted above are useful. Thepresent disclosure is related to a method of forming at least portionsof a rotor assembly for an electrical machine using a quasi-laminated orquasi-layered structure. Aspects of the disclosure will be described inthe context of a turbine engine generator. However, the disclosure isnot so limited and aspects described herein can have generalapplicability, including that the electrical machine can be utilized inany suitable mobile and non-mobile industrial, commercial, andresidential applications.

As used herein, the terms “additively manufactured” or “additivemanufacturing techniques or processes” refer generally to manufacturingprocesses wherein successive layers of material(s) are provided on eachother to “build-up,” layer-by-layer, a three-dimensional component. Thesuccessive layers generally fuse together to form a monolithic unitarycomponent, which can have a variety of integral sub-components.

Suitable additive manufacturing techniques in accordance with thepresent disclosure include, for example, Fused Deposition Modeling(FDM), Selective Laser Sintering (SLS), 3D printing such as by inkjetsand laserjets, Sterolithography (SLA), Direct Selective Laser Sintering(DSLS), Electron Beam Sintering (EBS), Electron Beam Melting (EBM),Laser Engineered Net Shaping (LENS), Laser Net Shape Manufacturing(LNSM), Direct Metal Deposition (DMD), Digital Light Processing (DLP),Direct Selective Laser Melting (DSLM), Selective Laser Melting (SLM),Direct Metal Laser Melting (DMLM), and other known processes.

In addition to using a direct metal laser sintering (DMLS) or directmetal laser melting (DMLM) process where an energy source is used toselectively sinter or melt portions of a layer of powder, it should beappreciated that according to alternative aspects of the presentdisclosure, the additive manufacturing process can be a “binder jetting”process. In this regard, binder jetting involves successively depositinglayers of additive powder in a similar manner as described above.However, instead of using an energy source to generate an energy beam toselectively melt or fuse the additive powders, binder jetting involvesselectively depositing a liquid binding agent onto each layer of powder.The liquid binding agent can be, for example, a photo-curable polymer oranother liquid bonding agent. Other suitable additive manufacturingmethods and variants are intended to be within the scope of the presentsubject matter.

In addition, one skilled in the art will appreciate that a variety ofmaterials and methods for bonding those materials can be used and arecontemplated as within the scope of the present disclosure. As usedherein, references to “fusing” can refer to any suitable process forcreating a bonded layer of any of the above materials. For example, ifan object is made from polymer, fusing can refer to creating a thermosetbond between polymer materials. If the object is epoxy, the bond can beformed by a crosslinking process. If the material is ceramic, the bondcan be formed by a sintering process. If the material is powdered metal,the bond can be formed by a melting or sintering process. One skilled inthe art will appreciate that other methods of fusing materials to make acomponent by additive manufacturing are possible, and the presentlydisclosed subject matter can be practiced with those methods.

In addition, the additive manufacturing process disclosed herein allowsa single component to be formed from multiple materials. Thus, thecomponents described herein can be formed from any suitable mixtures ofthe above materials. For example, a component can include multiplelayers, segments, or parts that are formed using different materials,processes, or on different additive manufacturing machines. In thismanner, components can be constructed which have different materials andmaterial properties for meeting the demands of any particularapplication. In addition, although the components described herein areconstructed entirely by additive manufacturing processes, it should beappreciated that in additional aspects of the present disclosure, all ora portion of these components can be formed via casting, machining, orany other suitable manufacturing process. Indeed, any suitablecombination of materials and manufacturing methods can be used to formthese components.

An exemplary additive manufacturing process will now be described.Additive manufacturing processes fabricate components usingthree-dimensional (3D) information, for example a three-dimensionalcomputer model, of the component. Accordingly, a three-dimensionaldesign model of the component can be defined prior to manufacturing. Inthis regard, a model or prototype of the component can be scanned todetermine the three-dimensional information of the component. As anotherexample, a model of the component can be constructed using a suitablecomputer aided design (CAD) program to define the three-dimensionaldesign model of the component.

The design model can include 3D numeric coordinates of the entireconfiguration of the component including both external and internalsurfaces of the component. For example, the design model can define thebody, the surface, and/or internal passageways such as passageways,voids, support structures, etc. In one exemplary non-limiting example,the three-dimensional design model is converted into a plurality ofslices or segments, e.g., along a central (e.g., vertical) axis of thecomponent or any other suitable axis. Each slice can define a thin crosssection of the component for a predetermined height of the slice. Theplurality of successive cross-sectional slices together form the 3Dcomponent. The component is then “built-up” slice-by-slice, orlayer-by-layer, until finished.

In this manner, the components described herein can be fabricated usingthe additive process, or more specifically each layer is successivelyformed, e.g., by fusing or polymerizing a plastic using laser energy orheat or by sintering or melting metal powder. For example, a particulartype of additive manufacturing process can use an energy beam, forexample, an electron beam or electromagnetic radiation such as a laserbeam, to sinter or melt a powder material. Any suitable laser and laserparameters can be used, including considerations with respect to power,laser beam spot size, and scanning velocity. The build material can beformed by any suitable powder or material selected for enhancedstrength, durability, and useful life, particularly at hightemperatures.

Each successive layer can be, for example, between about 10 μm and 200μm, although the thickness can be selected based on any number ofparameters and can be any suitable size according to alternative aspectsof the present disclosure. Therefore, utilizing the additive formationmethods described above, the components described herein can have crosssections as thin as one thickness of an associated powder layer, e.g.,10 μm, utilized during the additive formation process.

In addition, utilizing an additive process, the surface finish andfeatures of the components can vary as need depending on theapplication. For example, the surface finish can be adjusted (e.g., madesmoother or rougher) by selecting appropriate laser scan parameters(e.g., laser power, scan speed, laser focal spot size, etc.) during theadditive process, especially in the periphery of a cross-sectionallayer, which corresponds to the part surface. For example, a rougherfinish can be achieved by increasing laser scan speed or decreasing thesize of the melt pool formed, and a smoother finish can be achieved bydecreasing laser scan speed or increasing the size of the melt poolformed. The scanning pattern or laser power can also be changed tochange the surface finish in a selected area.

Notably, in exemplary non-limiting examples, several features of thecomponents described herein were previously not possible due tomanufacturing restraints. However, the present inventors haveadvantageously utilized current advances in additive manufacturingtechniques to develop such components generally in accordance with thepresent disclosure. While the present disclosure is not limited to theuse of additive manufacturing to form these components generally,additive manufacturing does provide a variety of manufacturingadvantages, including ease of manufacturing, reduced cost, greateraccuracy, etc.

All directional references (e.g., radial, axial, proximal, distal,upper, lower, upward, downward, left, right, lateral, front, back, top,bottom, above, below, vertical, horizontal, clockwise, counterclockwise,upstream, downstream, forward, aft, central, etc.) are only used foridentification purposes to aid the reader's understanding of the presentdisclosure, and do not create limitations, particularly as to theposition, orientation, or use of aspects of the disclosure describedherein. Connection references (e.g., attached, coupled, connected, andjoined) are to be construed broadly and can include intermediate membersbetween a collection of elements and relative movement between elementsunless otherwise indicated. As such, connection references do notnecessarily infer that two elements are directly connected and in fixedrelation to one another. The exemplary drawings are for purposes ofillustration only and the dimensions, positions, order and relativesizes reflected in the drawings attached hereto can vary.

Aspects of the disclosure can be implemented in any environment using anelectric motor regardless of whether the electric motor provides adriving force or generates electricity. For purposes of thisdescription, such an electric motor will be generally referred to as anelectric machine, electric machine assembly, or similar language, whichis meant to clarify that one or more stator/rotor combinations can beincluded in the machine. While this description is primarily directedtoward an electric machine providing power generation, it is alsoapplicable to an electric machine providing a driving force or anelectric machine providing both a driving force and power generation.Further, while this description is primarily directed toward an aircraftenvironment, aspects of the disclosure are applicable in any environmentusing an electric machine. Thus, a brief summary of a contemplatedenvironment should aid in a more complete understanding.

While “a set of” or “a plurality of” various elements will be described,it will be understood that “a set” or “a plurality” can include anynumber of the respective elements, including only one element.

FIG. 1 schematically illustrates an exemplary rotor assembly 10 that canbe utilized in any suitable electric machine, by way of non-limitingexample and includes beneficial aspects of the present disclosure. Therotor assembly 10 can include a rotor core 12 and a plurality of poles14, which are part of the rotor core 12 and extend from a centralportion thereof. While illustrated, by way of non-limiting example, ashaving four poles, it is contemplated that the plurality of poles 14 caninclude any number of poles spaced about the rotor core 12. Only fourpoles 14 have been shown for the sake of clarity, it will be understoodthat numerous poles including, by way of non-limiting example, twentypoles can be utilized on the rotor core 12. It will be understood thatwhile the rotor core 12 and the plurality of poles 14 have beenidentified with different numerals this is by way of designation forclarity and that the rotor core 12 and the plurality of poles 14 areunitarily formed, for example, by additively manufacturing to form amonolithic body.

A rotor shaft 16 can also be unitarily formed with the rotor core 12. Byway of non-limiting example, at least a first part 18 of the rotor shaft16 can be printed using additive manufacturing. It is furthercontemplated that at least a second part 19 of the rotor shaft 16 can beformed centrally within the rotor core 12. Alternatively, only a portionof the rotor core 12 and the rotor shaft 16 can be unitarily formed as amonolithic body.

Each pole of the plurality of poles 14 can include a pole body 20extending from the rotor core 12 towards a pole shoe 22. A curvedperipheral surface 26 is defined in a circumferential direction C by atan outside edge 28 of the pole shoe 22. Each pole shoe 22 extendsbetween a first end 30 and a second end 32 along an axial direction A.As used herein, the terms “axial” or “axially” refer to a dimensionalong a longitudinal axis, as illustrated by way of non-limitingexample, as the axial direction A along a center longitudinal axis X ofthe rotor shaft 16 disposed within the rotor assembly 10.

Teeth 40 can be unitarily formed in the pole shoe 22. The outside edge28 can at least in part define the teeth 40. Gaps 42 can be definedbetween adjacent teeth 40. The teeth 40 and the gaps 42 can be formedbetween the first end 30 and the second end 32 along a radial directionR. The illustration if the radial direction R in FIG. 1 is anon-limiting example of radial direction. As used herein, the terms“radial” or “radially” refer to a dimension extending between the centerlongitudinal axis X, an outer circumference or the outside edge 28, or acircular or annular component disposed thereof, such as, but not limitedto the curved peripheral surface 26. Gaps 42 can retain damper bars (notshown), the damper bars and the two end rings (not shown) form a damperwinding to help the dynamic performance of the generator of electricmachine and shield the harmonics into the core. Usually, the damper barsand the end rings are made of copper.

A rotor slot 50 can be located between two of the plurality of poles 14spaced about the rotor core 12. The rotor slot 50 can radially extendinto a portion of the pole body 20 so that the portion of the pole body20 partially defines the rotor slot 50. The rotor slot 50 can underlieand be defined by at least a part of the pole shoe 22. As defined by atleast a portion or part of the pole body 20 and the pole shoe 22, therotor slot 50 can extend into the rotor assembly 10 in a directionsubstantially orthogonal to the axial direction A.

Cooling tubes 54 can be unitarily formed through portions of the rotorcore 12. The cooling tubes 54 can be, by additive manufacturing, printedin each layer of the rotor core 12. The cooling tubes 54 can definecooling holes 56. The cooling holes 56 depicted in FIG. 1, as defined bythe cooling tubes 54, are printed such that each cooling hole 56 has ateardrop cross section as viewed from the perspective an axial view. Thecooling tubes 54 can be proximate the rotor slot 50. The location of thecooling tubes 54 relative to the rotor slot 50 can contribute to thecooling of the rotor windings (not shown in FIG. 1) that can be insertedin the rotor slot 50.

FIG. 2 schematically illustrates one of the plurality of poles 14 of therotor assembly 10. The pole 14 a illustrated in FIG. 2 further clarifiesthe structure of the pole shoe 22 extending from the pole body 20. Asdiscussed, the rotor assembly 10 can be unitarily formed using additivemanufacturing, so that the rotor assembly 10 can be formed by layinglaminate layers. The pole shoe 22 and portions of the pole body 20 canbe layered so that the unitary formation of the pole shoe 22 includesthe teeth 40 that define the gaps 42 by the printing of material orabsence of material in a laminate layer 58. The laminate layer 58 is anon-liming example of lamination layers that can be printed usingadditive manufacturing in a pattern that is relatively orthogonal to theaxial direction A. The thickness of the laminate layer 58 can vary basedon material and design of the printed rotor assembly 10 component. Itwill also be understood that while the term layer is user herein thatthe layer need not be uniform and that the layers need not be completelyseparate. In this manner, a set of support structures 60 can be formedwithin the pole shoe 22 between a first lamination 70 and a secondlamination 80.

More specifically, the set of support structures 60 within the pole shoe22 can result from the additive manufacturing process. In this manner,aspects of the present disclosure actually use quasi-laminations to formthe pole shoes 22. An example of quasi-laminations, by way ofnon-limiting example, can include the illustrated first lamination 70that extends along a first axial length 72, the second lamination 80that extends along a second axial length 82 and the set of supportstructures 60. The second axial length 82 is spaced from the first axiallength 72 by an intermediate axial length 64. The set of supportstructures 60 span the intermediate axial length 64. In this manner, theset of support structures 60 link the first lamination 70 and the secondlamination 80 such that they form a series of quasi-laminations and aunitary structure 90. Repeating the pattern of lamination layer andsupport structure layer can result in quasi-laminations defined along atleast a portion of an axial length of the at least a portion of the atleast one of the pole shoe 22 or the pole body 20. The axial length canbe from the first end 30 to the second end 32.

Voids 62 can be defined by two adjacent support structures of the set ofsupport structures 60. The adjacent support structures of the set ofsupport structures 60 that define the voids 62 can extend into the rotorcore 12 in the radial direction R.

A first radial location 94 can be located at the curved peripheralsurface 26. It is contemplated that the set of support structures 60 andvoids 62 can extend through at least a portion of the pole shoe 22 inthe radial direction R toward the rotor core 12; terminating at a secondradial location 96. That is, the set of support structures 60 and thevoids 62 can extend radially from the first radial location 94 to asecond radial location 96.

Holes 92 can be defined within the pole 14. The holes 92 can extendthrough the pole 14 a in relatively circumferential direction C that canbe substantially orthogonal to both the radial direction R and the axialdirection A. The holes 92 can intersect one or more set of supportstructures 60. The location of the intersection of the holes 92 and theset of support structures 60 can be at the second radial location 96.

Alternatively or additively, the holes 92 can intercept the set ofsupport structures 60 and voids 62 at a location other than the secondradial location 96. It is contemplated that the holes 92 can intersectthe set of support structures 60 and voids 62 at any location ordirection. It is further contemplated that the pole 14 a can includemore than one hole 92 through the set of support structures 60. In anon-limiting example, the holes 92 do not penetrate or break any portionof the rotor shaft 16. In another non-limiting example, the holes 92 donot penetrate or break any portion of the gaps 42. In yet anothernon-limiting example, the holes 92 do not pass through cooling tubeslocated radially.

FIG. 3 illustrates a top view of the pole 14 a. The top view of the pole14 a provides additional detail to the set of support structures 60 thatdefine the voids 62 that can result from the quasi-lamination formationof the unitary structure 90.

Quasi-laminations can include laminate layers of non-uniformly dispensedmaterial formed between laminate layers of uniformly dispensed materialsuch that the layers are connected instead of spaced apart. For example,by way of non-limiting illustration, the first lamination 70 can includelaminate layers of uniformly dispensed material. The uniformly dispensedmaterial laminate layers of the first lamination 70 are laid for thefirst axial length 72.

The set of support structures 60 can be defined by laminate layers ofnon-uniformly dispensed material. In layers of non-uniformly dispensedmaterial, there can be locations that receive material and locationsthat do not receive material. A first arch 66 can result from locationsthat receive material in the laminate layers of non-uniformly dispensedmaterial. The first arch 66 is unitarily formed to the first lamination70. Optionally, the first arch 66 can be approximately half of theintermediate axial length 64.

A second arch 68 can result from locations that receive material in thelaminate layers of non-uniformly dispensed material. The second arch 68is unitarily formed to the first arch 66. The first arch 66 and secondarch 68 define the set of support structures 60 that span theintermediate axial length 64.

The set of support structures 60 are illustrated, by way of non-limitingexample, as circular. The voids 62 defined by two adjacent supportstructures of the set of support structures 60, can be formed duringquasi-lamination as locations that do not receive material in thelaminate layers of non-uniformly dispensed material. The voids 62 areillustrated, by way of non-limiting example, as a circle based on thecircular shape of the two adjacent support structures of the set ofsupport structures 60 that define the void 62.

The second lamination 80 can include laminate layers of uniformlydispensed material that are formed unitarily to the second arch 68 andcan extend the second axial length 82.

By way of additional non-limiting example, a left support structure 67and a right support structure 69 can alternatively form two adjacentsupport structures of the set of support structures 60. In theillustrated example, the left support structure 67 and the right supportstructure 69 span the intermediate axial length 64. The left supportstructure 67 is defined by a body that spans a predetermined distancebetween a first arc 73 and a second arc 74. The first arc 73 and thesecond arc 74 are substantially orthogonal to the first lamination 70and the second lamination 80. The right support structure 69 is definedby a body that spans a predetermined distance between a third arc 76 anda fourth arc 77. The third arc 76 and the fourth arc 77 aresubstantially orthogonal to the first lamination 70 and the secondlamination 80. Both the bodies of the of the left support structure 67and the right support structure 69 span between the first lamination 70and the second lamination 80. The placement of the left supportstructure 67 and the right support structure 69 effectively forms a void63 there between. The void 63 is similar in shape to the void 62,although this need not be the case. As with the support structuresdescribed above, the left support structure 67 and the right supportstructure 69 are unitarily formed with the first lamination 70 and thesecond lamination 80 to form quasi laminations.

By way of non-limiting example, the intermediate axial length 64 of theset of support structures 60 can be a maximum of 0.005 inches (0.127millimeters) or less. The first axial length 72 of the first lamination70 can be a maximum 0.030 inches (0.762 millimeters) or less. The secondaxial length 82 of the second lamination 80 can be 0.030 inches (0.762millimeters) or less.

It is contemplated that at a least a portion of the first lamination 70or the second lamination 80 can be formed from by laminate layers ofnon-uniformly dispensed material. It is further contemplated that thethickness or shape of the first lamination 70, the set of supportstructures 60, or the second lamination 80 can vary.

FIG. 4 illustrates a top view of a pole 114 a, according to anotheraspect disclosed herein. The pole 114 a is substantially similar to thepole 14 a. Therefore, like parts will be identified with like numeralsincreased by 100, with it being understood that the description of thelike parts of the pole 14 a applies to the pole 114 a unless otherwisenoted.

A set of support structures 160 are illustrated, by way of non-limitingexample, as elliptical. Voids 162 defined by two adjacent supportstructures of the set of support structures 160 are similarlyillustrated, by way of non-limiting example, as elliptical.Alternatively, the set of support structures 160 can be a diamond or anyother regular or irregular shape or any shapes that can perform theequivalence. Similarly, voids 162 can have a shape that is a diamond, orany other regular or irregular shape or any shapes that can perform theequivalence. It is further contemplated that the set of supportstructures 160 can be a variety of shapes that can vary from support tosupport.

By way of non-limiting example, an intermediate axial length 164 of aset of support structures 160 can be 0.005 inches (0.127 millimeters) orless. A first axial length 172 of a first lamination 170 can be 0.030inches (0.762 millimeters) or less. A second axial length 182 of asecond lamination 180 can be 0.030 inches (0.762 millimeters) or less.

It is contemplated that the intermediate axial length 164 defined by theset of support structures 160 in the axial direction A can varydepending on design. While illustrated as very thin, it is alsocontemplated that the thickness, frequency of occurrence, and shape ofthe set of support structures 160 can also vary in any direction.Similarly, it is contemplated that the first lamination 170 or thesecond lamination 180 can have varying thickness and shape.

FIG. 5 depicts a flow chart diagram used to illustrate a method 200 formanufacturing the rotor assembly 10 for an electrical machine. Formingcan, by way of non-limiting example, include one or more of casting,additive manufacturing, or electrical discharge machining (EDM).Additive manufacturing can, by way of non-limiting example, includerapid prototyping, selective laser sintering, or printing. Printing, byway of non-limiting example, can include direct metal laser melting.

Optionally, at 202, at least a portion of the rotor shaft 16 is formed.By way of non-limiting example, at least a portion of the rotor shaft 16can be printed layer by layer until reaching a predetermined rotor shaftdesign or height. The printing of at least part of the rotor shaft 16,at 202, can occur prior to, concurrent with, or following any otherformation of portions of the rotor assembly 10. It is contemplated thatthe first part 18 of the rotor shaft 16 can be printed of a steel alloy,such as a #4340 steel alloy containing at least one of nickel, chromium,or molybdenum. Other suitable materials can be used without deviatingfrom the scope of the present disclosure.

At 204, a central portion of the rotor core 12 is formed. By way ofnon-limiting example, the rotor core 12 can be printed layer by layeruntil reaching a predetermined rotor core design, height, or radius. Byway of non-limiting example, the predetermined rotor core design caninclude the printing, at 204, of the cooling tubes 54 as part of therotor core 12. The cooling tubes 54 can be printed in each layer of therotor core 12. It is contemplated, at 204, that the predetermined rotorcore design can include printing a rotor shaft section for the rotorshaft 16 passing through the rotor core 12. In this manner, printing at202 and 204 can occur simultaneously.

The rotor core 12 can be printed using, for instance, aniron-cobalt-vanadium soft magnetic alloy. Other suitable materials canbe used without deviating from the scope of the present disclosure.Optionally, at 204, the printing of central portion of the rotor core 12can include varnishing the rotor core 12.

At 206, pole portions of the rotor assembly 10 are formed spaced aboutthe central portion of the rotor core 12. By way of non-limitingexample, the plurality of poles 14 can be printed until reaching apredetermined plurality of poles design or height. The printing of theplurality of poles at 206 can occur prior to, concurrent with, orfollowing the printing of the rotor core 12 at 204 or the printing of atleast part of the rotor shaft 16 at 202. While the printing at 204 andat 206 have been shown sequentially it will be understood that they mostlikely will be printed simultaneously because the rotor core 12 andplurality of poles 14 are on the same printing plane.

A non-limiting example of a predetermined plurality of poles design caninclude each of the plurality of poles 14 having the pole body 20extending in the radial direction R from the rotor core 12 towards thepole shoe 22. At least a portion of the pole shoe 22 or pole body 20 isprinted using the quasi-laminations as described above. Thequasi-laminations can be used to form the predetermined plurality ofpoles design that can include the teeth 40 and the gaps 42 that areformed in the pole shoe 22. Additionally, the quasi-laminations can beused to form the unitary structure 90 within at least a portion of thepole shoe 22 or pole body 20. The unitary structure 90 including thefirst lamination 70, the set of support structures 60, and the secondlamination 80.

By way of non-limiting example, the quasi-laminations can include thefirst lamination 70. The first lamination 70 can be printed usinglaminate layers of uniformly dispensed material. The uniformly dispensedmaterial laminate layers are printed or otherwise formed via additivemanufacturing for the first axial length 72 to form the first laminate70.

Once the first laminate 70 is formed, printing can continue to form theset of support structures 60 using laminate layers of non-uniformlydispensed material. The printing or otherwise forming via additivemanufacturing of the set of support structures 60 can begin by theprinting of the first arch 66. The first arch 66 can results fromlocations that receive material in the laminate layers of non-uniformlydispensed material. The first arch 66 is unitarily formed to the firstlamination 70. Optionally, the first arch 66 can be approximately halfof the intermediate axial length 64.

The second arch 68 is formed similarly, by adding laminate layers ofnon-uniformly dispensed material to the completed first arch 66. Thefirst arch 66 and second arch 68 define the set of support structures 60that span the intermediate axial length 64.

The voids 62 defined by the set of support structures 60, can be formedduring quasi-lamination as locations that do not receive material in thelaminate layers of non-uniformly dispensed material. Alternatively, thevoids 62 defined by the set of support structures 60 can be formed inthe quasi-laminations using EDM.

The second lamination 80 can be printed or otherwise formed via additivemanufacturing to the set of support structures 60 as laminate layers ofuniformly dispensed material that extend the second axial length 82.

Quasi-laminations allow the first lamination 70, the set of supportstructures 60, and the second lamination 80 to form the unitarystructure 90. The unitary structure 90 formed using quasi-laminationscan extend in the radial direction R through an entirety of the poleshoe 22 and a portion of the pole body 20.

Upon completion of this process, a distal end of the second lamination80 can become the beginning of a new first lamination and the processcan repeat itself until the desired length is achieved. In this manner,the unitary structure 90 can be formed from multiple layers ofquasi-laminations with sets of support structures between the lamination“layers.”

Alternatively, additional lamination layers and support structure layerscan be printed in any desired pattern where a layer is not limited asonly providing lamination or support structure. By way of non-limitingexample, the first axial length 72 of the first lamination 70 can begreater than the second axial length 82 of the second lamination 80.Another non-limiting example can include an alternation in the shape ofthe set of support structures 60. That is, the unitary structure 90 caninclude both circular and elliptical shaped voids 62 defined by the setof support structures 60 or can be spaced or staggered in any suitablemanner.

It is also contemplated that an insulating material can be printed intoat least a portion of the void 63 or voids 62, 162. Additionally oralternatively, insulating material can be added to at least a portion ofthe void 63 or voids 62, 162 after one or more of the set of supportstructures 60 are formed, printed, or otherwise manufactured.

The plurality of poles 14 can be formed at 206 using, for instance, aniron-cobalt-vanadium soft magnetic alloy. Other suitable materials canbe used without deviating from the scope of the present disclosure.

Additionally or alternatively, printing the plurality of the poles at206 can include direct metal laser melting. Optionally, at 206, theprinting of the plurality of poles 14 can include varnishing theplurality of poles 14.

The forming of the rotor core 12 at 204 or the forming of plurality ofpoles 14 at 206 can result in formation of the rotor slot 50 betweeneach of the plurality of poles 14.

Those of ordinary skill in the art, using the disclosures providedherein, will understand that the method 200 disclosed herein can beadapted, expanded, modified, omitted, performed simultaneously, and/orrearranged in various ways without deviating from the scope of thepresent disclosure.

Aspects of the present disclosure provide for a variety of benefits.Traditional methods of forming metal laminates, such as rolling andstamping, have an inherent variance in laminate thickness such as tenpercent, which can lead to non-uniform component lengths when stacks areformed from multiple laminates. The inclusion of the quasi-laminationcan decrease variance. It is also contemplated that quasi-lamination canrequire less material than a design that includes uniform distributionof material in every laminate layer. This can provide cost or timesavings in the manufacturing process.

Utilizing additive manufacturing methods, even multi-part components canbe formed as a single piece of continuous metal, and can thus includefewer sub-components and/or joints compared to prior designs. Theintegral formation of these multi-part components through additivemanufacturing can advantageously improve the overall assembly process.For example, the integral formation reduces the number of separate partsthat must be assembled, thus reducing associated time and overallassembly costs. Additionally, existing issues with, for example,leakage, joint quality between separate parts, and overall performancecan advantageously be reduced.

The additive manufacturing methods described herein enable much morecomplex and intricate shapes and contours of the components describedherein. For example, such components can include quasi-laminations,which can include laminate layers connected by support structures. Thesuccessive, additive nature of the manufacturing process enables theconstruction of these novel features. As a result, the componentsdescribed herein can exhibit improved performance and reliability.

While the gaps defined between the teeth of the pole shoe are known tohelp reduce eddy currents, the voids defined by support structuresformed by using quasi-lamination further limit eddy currents. The designthat includes both gaps and voids can reduce eddy current losses andreduce the sink effect during operation of an electrical machine forwhich the rotor core is utilized.

To the extent not already described, the different features andstructures of the various aspects can be used in combination with eachother as desired. That one feature cannot be illustrated in all of theaspects is not meant to be construed that it cannot be, but is done forbrevity of description. Thus, the various features of the differentaspects can be mixed and matched as desired to form new examples,whether or not the new examples are expressly described. Combinations orpermutations of features described herein are covered by thisdisclosure.

This written description uses examples to disclose aspects of theinvention, including the best mode, and also to enable any personskilled in the art to practice aspects of the invention, includingmaking and using any devices or systems and performing any incorporatedmethods. The patentable scope of the invention is defined by the claims,and can include other examples that occur to those skilled in the art.Such other examples are intended to be within the scope of the claims ifthey have structural elements that do not differ from the literallanguage of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims.

What is claimed is:
 1. A method for manufacturing a rotor assembly foran electrical machine, the method comprising: forming a rotor core; andforming a plurality of poles, the plurality of poles spaced about therotor core, each pole of the plurality of poles having a pole bodyextending from the rotor core towards a pole shoe defining a curvedperipheral surface; wherein forming at least a portion of at least oneof the plurality of poles comprises forming quasi-laminations thatinclude a first lamination extending along a first axial length, asecond lamination extending along a second axial length and a set ofsupport structures and wherein the second axial length is spaced fromthe first axial length by an intermediate axial length and the set ofsupport structures span the intermediate axial length wherein at leasteach pole comprises a unitary structure, wherein the unitary structureof the first lamination, the second lamination, and the set of supportstructures extends from a first end of the pole shoe to a second end ofthe pole shoe and the set of support structures extends radially throughan entirety of the pole shoe and a portion of the pole body.
 2. Themethod of claim 1 wherein the set of support structures define a set ofvoids within the unitary structure.
 3. The method of claim 2 wherein atleast one of the set of voids is at least one of a circle, an ellipse,or a diamond.
 4. The method of claim 1 wherein forming the set ofsupport structures comprises additively manufacturing supportingstructures having a maximum of 0.005 inches (0.127 millimeters) in axiallength or less and wherein the first lamination and the secondlamination are 0.030 inches (0.762 millimeters) or less.
 5. The methodof claim 1 wherein forming the plurality of poles includes direct metallaser melting, additive manufacturing, or electrical dischargemachining.
 6. The method of claim 5 wherein forming the rotor corefurther comprises forming cooling tubes via direct metal laser melting,additive manufacturing, or electrical discharge machining as part of therotor core.
 7. The method of claim 1, wherein the rotor core and theplurality of poles are formed by additive manufacturing.
 8. The methodof claim 7 wherein the set of support structures define voids within theunitary structure.
 9. The method of claim 7 wherein additivelymanufacturing the set of support structures comprises additivelymanufacturing at least one of circles, ellipses, or diamonds.
 10. Themethod of claim 7 wherein additively manufacturing the rotor corefurther comprises additively manufacturing cooling tubes as part of therotor core.
 11. The method of claim 7 wherein additively manufacturingthe rotor core comprises varnishing the rotor core.
 12. The method ofclaim 7, further comprising additively manufacturing a first part of arotor shaft.
 13. The method of claim 12 wherein the first part of therotor shaft is additively manufactured using a first material andwherein the quasi-laminations used to form at least a portion of therotor core are additively manufactured using a second material that isdifferent than the first material.
 14. The method of claim 7 whereinadditively manufacturing the plurality of poles includes printing theplurality of poles.
 15. The method of claim 7 wherein additivelymanufacturing the plurality of poles comprises direct metal lasermelting.
 16. A rotor assembly for an electric machine, comprising: arotor core; and a plurality of poles, the plurality of poles spacedabout the rotor core and unitarily formed with the rotor core, each poleof the plurality of poles having a pole body extending from the rotorcore towards a pole shoe defining a curved peripheral surface; whereinat least a portion of at least one of the pole shoe or the pole bodycomprises quasi-laminations defined along at least a portion of an axiallength of the at least a portion of the at least one of the pole shoe orthe pole body, and wherein quasi-laminations include a unitary structureincluding a first lamination extending along a first axial length, asecond lamination extending along a second axial length and a set ofsupport structures wherein the second axial length is spaced from thefirst axial length by an intermediate axial length and the set ofsupport structures span the intermediate axial length, wherein the setof support structures extend radially through an entirety of the poleshoe and a portion of the pole body and the first lamination, the secondlamination, and the set of support structures extend axially from afirst end of the pole shoe to a second end of the pole shoe.
 17. Therotor assembly of claim 16 wherein the set of support structures definevoids within the unitary structure.
 18. The rotor assembly of claim 17wherein the set of support structures define voids including at leastone of circles, ellipses, or diamonds.
 19. The rotor assembly of claim16 wherein the set of support structures are a maximum of 0.005 inches(0.127 millimeters) in axial length or less.
 20. The rotor assembly ofclaim 19 wherein at least one of the first axial length or the secondaxial length is a maximum of 0.030 inches (0.762 millimeters) or less.21. The rotor assembly of claim 16 wherein the pole shoe furthercomprises teeth and gaps formed between the first end of the pole shoeand the second end of the pole shoe and the quasi-laminations form theteeth and the gaps.
 22. The rotor assembly of claim 16, furthercomprising a rotor slot located between two of the plurality of polesspaced about the rotor core and wherein the rotor slot extends in adirectional substantially orthogonal to the axial length.
 23. The rotorassembly of claim 16, further comprising a portion of a rotor shaftlocated centrally within the rotor core and unitarily formed therewith.24. A rotor assembly for an electric machine, comprising: a rotor core;and a plurality of poles, the plurality of poles spaced about the rotorcore and unitarily formed with the rotor core, each pole of theplurality of poles having a pole body extending from the rotor coretowards a pole shoe defining a curved peripheral surface; wherein atleast a portion of at least one of the pole shoe or the pole bodycomprises quasi-laminations defined along at least a portion of an axiallength of the at least a portion of the at least one of the pole shoe orthe pole body, and wherein quasi-laminations include a unitary structureincluding a first lamination extending along a first axial length, asecond lamination extending along a second axial length and a set ofsupport structures wherein the second axial length is spaced from thefirst axial length by an intermediate axial length and the set ofsupport structures span the intermediate axial length, and wherein thefirst lamination, the second lamination, and the set of supportstructures extend axially from a first end of the pole shoe to a secondend of the pole shoe, and wherein the pole shoe further includes teethand gaps formed between the first end of the pole shoe and the secondend of the pole shoe and the quasi-laminations form the teeth and thegaps.
 25. The rotor assembly of claim 24 wherein the set of supportstructures define voids within the unitary structure.
 26. The rotorassembly of claim 25 wherein the set of support structures define voidsincluding at least one of circles, ellipses, or diamonds.
 27. The rotorassembly of claim 24, further comprising a rotor slot located betweentwo of the plurality of poles spaced about the rotor core and whereinthe rotor slot extends in a directional substantially orthogonal to theaxial length.